WEEKLY WATER NEWS

DataStreme WES Week Nine: 27-31 March 2006

Water in the News:

(Thur.) Salt and dust in ice cores help identify past climate -- Scientists with the British Antarctic Survey report detecting small amounts of dust and salt trapped in a 3-km long ice core extracted from the East Antarctic plateau, indicating significant periodic changes in Antarctic and South American climate during the last 740,000 years. They suggest that each time the planet emerged from an ice age, southern South America became drier or windier with much dust carried to Antarctica, while the Antarctic sea ice extent responded more slowly, affecting the amount of airborne salt deposited on the ice cap. [EurekAlert!]
(Thur.) Monitoring the "Land of 10,000 Lakes" from the air -- Researchers with the University of Minnesota, the University of Nebraska and the Minnesota Pollution Control Agency have been using an airplane equipped with hyperspectral sensor to monitor the water quality of the Mississippi River and lakes in the Minneapolis-St. Paul metropolitan area. [US Water News Online]
(Thur.) Using microbes to fight groundwater contamination -- A researcher at Rutgers University has been developing a technique whereby microbes can remove the carcinogenic and toxic gasoline additive methyl tertiary-butyl ether from groundwater. [EurekAlert!]
(Tues.) A new iceberg is detected -- Scientists with the National Ice Center report that visible images from Defense Meteorological Satellite Program satellites indicate that a large iceberg, identified as iceberg D-16, recently broke from an ice sheet in Antarctica's Queen Maud Land and entered the Weddell Sea. [NOAA News]
(Tues.) Groundwater is not exploited in Israel -- In producing a hydrological mapping study of the Judean desert, scientists at the Hebrew University of Jerusalem have concluded that a large underground water reservoir called the Judea Group Aquifer is not only available but currently not fully exploited by Israel, which is short of usable water. [EurekAlert!]
(Tues.) Changes in agricultural practices could help slow warming trend -- Climate researchers at the Lawrence Livermore National Laboratory claim that the output from their climate models indicates that recent changes in agricultural practices around the world appear to have slowed the increases in global temperatures as compared with results when these factors were not taken into account. [Lawrence Livermore National Laboratory]
(Tues.) Satellites aid in search for clean drinking water -- In commemoration of World Water Day last week, the European Satellite Agency posted a description of how radar altimeters onboard satellites from that agency, along with those from NASA and the French Space Agency, have been used to provide high resolution data on water in a variety of reservoirs around the world. [ESA]
Tsunami Awareness Week in Alaska -- The Governor of Alaska, along with NOAA, has proclaimed next week (26 March-1 April 2006) as Tsunami Awareness Week in Alaska. The start of this week coincides with the 42^nd anniversary of the series of devastating tsunamis that struck southeastern Alaska following several earthquakes. [Governor's Office] As a part of Tsunami Awareness Week, a statewide test of the tsunami warning communications system in Alaska will be conducted on Wednesday. [NOAA News]
Water problems and solutions discussed -- Some items from the 4th World Water Forum that was held last week in Mexico City include:
- Several speakers, including the former Prime Minister of France and the executive director of the International River Network, told participants that agriculture consumes most of the water worldwide and is responsible for much of its waste. They suggest that elimination of mismanagement and water waste could help alleviate the current worldwide water crisis. [ENN]
- Representatives from 148 countries attending the Forum concluded that governments, not private companies, should take the lead at improving public access to clean water. [ENN]
- The Bolivian Water Minister told the press that his government will not sign the international declaration on the importance of clean water made at the Forum because the declaration fails to claim that access to clean water is a human right. [ENN]
Early snowmelt appears to be occurring in eastern North America -- A recently released US Geological Survey report indicates that winter and spring flow in many rivers in the northern tier of states and eastern Canada are occurring at least one week earlier during the last 50 years than during the first half of the 20th century, suggesting an earlier snowmelt. [EurekAlert!]
Monitoring glaciers by repeat photographs -- The US Geological Survey recently unveiled a new website that includes a collection of photographs taken in and around Glacier National Park, MT by USGS scientists involved with the Global Change Research Project paired with historical photographs to document the glacial recession in the last century. [USGS]
Mapping of floods by satellites aids in protecting the public -- Civil defense officials in eastern France are relying upon the rapid flood mapping service funded by the European Space Agency that would provide a variety of map products from several sensor types onboard the agency satellites within hours of the start of a flood emergency. [ESA]
Glacial earthquakes studied in Greenland -- Seismologists at Harvard University and Lamont-Doherty Earth Observatory have been found that "glacial earthquakes" in Greenland are not only a seasonal phenomenon as they occur most frequently in summer, but have also doubled in number within the last three years. These glacial earthquakes, occurring when glaciers lurch forward, appear to indicate warmer conditions. [EurekAlert!] In a related article, a glaciologist at the University of Washington suggests that during calving where Greenland glaciers lose large pieces of ice along their leading edge, openings are created where ice streams through more quickly. [EurekAlert!]
Global and US Hazards/Climate Extremes -- A review and analysis of the global impacts of various weather-related events, including drought, floods and storms during the current month. [NCDC]
Global Water News Watch -- Other water news sources can be obtained through the SAHRA Project at the University of Arizona [SAHRA Project]
Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Seiche

You probably remember as a child agitating the bath water so that it sloshed back and forth in the tub. (If you never did this as a child, there's still time.) You produced a seiche, a phenomenon first studied in Lake Geneva, Switzerland in the 1700s. A seiche (pronounced "say-sh") is a rhythmic oscillation of water in an enclosed basin (e.g., bathtub, lake, or reservoir) or a partially enclosed coastal inlet (e.g., bay, harbor, or estuary). With this oscillation, the water level rises at one end of a basin while simultaneously dropping at the other end. A seiche episode may last from a few minutes to a few days.

A seiche is a standing wave. Whereas wind-driven waves (pages 181-182 in your DataStreme WES textbook) are progressive in that they propagate through a body of water, standing waves are stationary. With progressive waves, crests and troughs travel along the water surface but with standing waves, crests alternate vertically with troughs at fixed locations. For both progressive and standing waves, the restoring force is gravity.

With a typical seiche in an enclosed basin, the water level near the center does not change at all although that is where the water exhibits its greatest horizontal movement; this is the location of a node. At either end of an enclosed basin, vertical motion of the water surface is greatest (with minimal horizontal movement of water); these are locations of antinodes. The motion of the water surface during a seiche is somewhat like that of a seesaw: The balance point of the seesaw does not move up or down (analogous to a node) while people seated at either end of the seesaw move up and down (analogous to an antinode).

Go to the University of Delaware's Seiche Calculator at http://www.coastal.udel.edu/faculty/rad/seiche.html. Set the "Modal Number" to 1 and then press "Calculate" for a graphical simulation of a seiche in an enclosed basin.

Partially enclosed basins usually have a node located at the mouth (rather than near the center) and an antinode at the landward end. Go to the Seiche Calculator, set the "Modal Number" to 0.5 and then press "Calculate" for a simulation of a seiche in a basin open to the right. Furthermore, some basins are complex and have multiple nodes and antinodes; these can be simulated on the Seiche Calculator by selecting different values of "Modal Number" greater than one.

A seiche can be induced by wind, regional differences in air pressure, earthquakes, or tidal forces. For example, wind blowing persistently in the same direction down the long axis of a bay causes water to pile up at the downwind end of the bay. When the wind slackens, the water oscillates (as a seiche) back-and-forth from one end of the bay to the other until eventually the water calms to a horizontal surface. A line of thunderstorms moving eastward from Wisconsin in late May 1998 produced a seiche in Lake Michigan that killed several people by drowning at the southern end of the lake. Previous seiches have produced 8 to 10 ft waves on Lake Michigan. A tsunami generated a seiche in the harbor of Hilo, HI following a major earthquake in the Aleutian Islands on 1 April 1946.

The natural period of a seiche depends on the length and depth of the basin and generally ranges from minutes to hours: The period is directly proportional to basin length. For example, the natural period of a seiche in a small pond is considerably shorter than its period in a large coastal inlet. In addition, for the same basin, the natural period is inversely proportional to water depth; that is, the period shortens as water deepens. Using the Seiche Calculator, you may wish to experiment with different values of basin length and depth. Conversely, one can estimate the average depth of a lake by determining the period of the seiche and the length of the lake.

Usually a seiche in a lake or harbor is of little concern because the changes in water level are minor--often only a few centimeters. Under certain circumstances, however, a seiche may grow to great heights with serious consequences including flooding and damage to moored vessels. A seiche grows as a consequence of resonance, that is, when the period of the disturbance (e.g., wind, earthquake) matches the natural oscillation period of a specific basin. Recall again your youthful bathtub experience. By timing your rhythmic disturbance of the water to match the natural period of the tub (about one second), you were able to cause the seiche to build until the water splashed out of the tub and onto the floor. Through resonance, vibrations from the 1994 Northridge, CA earthquake caused swimming pools to overflow throughout Southern California. In bays open to the ocean, if the period of tidal forcing matches the natural period of the bay, resonance can greatly increase the tidal range.

Concept of the Week: Questions

Seiches are [(standing) (progressive)] waves.
The natural period of a seiche [(depends on) (is independent of)] the size of an enclosed basin.

Historical Events:

27-28 March 1964...The most powerful earthquake in US history, the Good Friday Earthquake, rocked south central Alaska, killing 125 people and causing $311 million in property damage, especially to the city of Anchorage. The earthquake in Prince William Sound, which had a magnitude of 9.2 on the Richter scale, caused some landmasses to be thrust upward locally as high as 80 feet, while elsewhere land sank as much as 8 feet. This earthquake and submarine landslides also created a tsunami that produced extensive coastal damage. A landslide at Valdez Inlet in Alaska generated a tsunami that reached a height of 220 feet in the inlet. A major surge wave that was approximately 100 ft above low tide caused major damage to Whittier (where 13 died) and other coastal communities in Alaska. The first wave took more than 5 hours to reach the Hawaiian Islands where a 10-foot wave was detected, while a wave that was 14.8 feet above high tide level traveled along portions of the West Coast, reaching northern California 4 hours after the earthquake. Nearly 10,000 people jammed beaches at San Francisco to view the possible tsunami, but no high-amplitude waves hit those beaches. Tsunami damage reached Crescent City in northern California. Tens of thousands of aftershocks indicated that the region of faulting extended about 600 miles. The Alaska Tsunami Warning Center was established in the wake of this disaster, with a mission to warn Alaskan communities of the threat from tsunamis. [See the 1964 Prince William Sound Tsunami page from the University of Washington.] (Accord's Weather Guide Calendar) ( US Coast Guard Historians Office)
27 March 1980...Waves to 20 ft and winds to 58 mph in the North Sea southwest of Stavanger, Norway led to the collapse of an oil rig accommodation platform. The deaths of 123 of the 212 people on the platform represents the world's worst drilling catastrophe. (Accord's Weather Guide Calendar)
28 March 1902...McMinnville, TN (elevation 900 ft) received 11.00 in. of precipitation, setting a 24-hour precipitation record for the Volunteer State. (National Climate Data Center).
28 March 1980...Although springtime was starting in the Rocky Mountains, the snow just kept on coming! One foot or more of snow fell over portions of eastern Colorado, southwest Nebraska, northwest Kansas and southeastern Wyoming. Winds reached 40 mph and Valentine, NE received 13 in. of snow. North Platte, NE checked in with 15 in. (Intellicast)
28 March 1998...Three Boy Scout troop members died when their sport utility vehicle was swept away as they tried to cross a running wash just north of Sunflower, AZ. (Accord's Weather Guide Calendar)
29 March 1886...Atlanta, GA was drenched with a record 7.36 in. of rain in 24 hours. (The Weather Channel)
29 March 1920...Clear Spring, MD received 31 inches of snow in 24 hours to establish a state record. (Sandra and TI Richard Sanders - 1987)
29 March 1980...Heavy rains produced mudslides in Natchez, MS. The slides covered two buildings on Silver Street, killing 3 people and injuring 4. (Intellicast)
29 March 1989...Thunderstorms produced torrential rains in northeastern Texas and southwestern Arkansas. Longview, TX reported 14.16 in. of rain. More than 11 in. of rain at Henderson, TX caused a dam to give way, and people stranded in trees had to be rescued by boat. Total damage in northeastern Texas was estimated at $10 to 16 million. (The National Weather Summary) (Storm Data)
29-31 March 1848...An ice dam at the neck of Lake Erie and the entrance to the Niagara River between Fort Erie, ON and Buffalo, NY caused by wind, waves and lake currents stopped flow of water over Niagara Falls for 30 hours, commencing during the late hours of the 29^th. (Accord's Weather Guide Calendar) (The Weather Doctor)
31 March 2000...The water temperature of Lake Erie at Buffalo, NY was 39 degrees Fahrenheit on the last day of March, tying the maximum temperature for the date with that of 1998. Ice was present in 61 of 74 years on the 31^st, but this was third year in a row with open water. (Accord's Weather Guide Calendar)
1 April 1946...The Scotch Cap Lighthouse on Unimak Island in Alaska's Aleutian Islands was shaken by two earthquakes in a 27 minute span, then obliterated by a tsunami wave. The entire five-man crew was killed and the lighthouse antenna (105 ft above sea level) was washed away. Some debris was found 115 ft above sea level. The tsunami that propagated across the Pacific Ocean was responsible for more than 165 fatalities and over $26 million in damage. Many of the casualties were on the Hawaiian Islands, especially in Hilo on the Big Island. This tsunami was responsible for the development of the current Pacific Tsunami Warning System. (University of Washington) (Accord's Weather Guide Calendar) (US Coast Guard Historian's Office)
2 April 1958...One of the most destructive coastal storms in years battered New England (31 March-3 April). Some beaches between Portland, ME and Cape Cod, MA were eroded by approximately 50 ft. Miles of sea walls and bulkheads were either breached or demolished. Many beachfront cottages in Massachusetts, New Hampshire and Maine were sandblasted. (Accord's Weather Guide Calendar)
2 April 1997...An intense winter storm slammed the Maritime Provinces. Freezing rain knocked out power to more than 4,000 homes on Prince Edward Island. (The Weather Doctor)
3 April 1982...Wind-driven ice from Lake Winnebago in east central Wisconsin piled to 40-ft heights on the lake's eastern shoreline, damaging buildings in the Stockbridge area. Winds reached 80 mph across Wisconsin. (Accord's Weather Guide Calendar)